명품 C++ 4장 연습문제 - 실습 문제

1.

#include <iostream>
using namespace std;

class Color{
    int red, green, blue;
public:
    Color() { red = green = blue = 0; }
    Color(int r, int g, int b) { red = r; green = g; blue = b; }
    void setColor(int r, int g, int b) { red = r; green = g; blue = b; }
    void show() { cout << red << ' ' << green << ' ' << blue << endl; }
};

int main() {
    Color screenColor(255, 0, 0);
    Color *p;
    p = &screenColor;
    p->show();
    Color colors[3];
    p = colors;

    p->setColor(255, 0, 0);
    (p + 1)->setColor(0, 255, 0);
    (p + 2)->setColor(0, 0, 255);

    for (int i = 0; i < 3; i++) {
        (p + i)->show();
    }
}

2.

#include <iostream>
using namespace std;

int main() {
    int *arr = new int[5];
    cout << "정수 5개 입력>> ";
    double sum = 0;
    for (int i = 0; i < 5; i++) {
        cin >> arr[i];
        sum += arr[i];
    }
    cout << "평균 " << sum / 5 << endl;
    delete[] arr;
}

3.

#include <iostream>
#include <string>
using namespace std;

// (1)
int main() {
    string text;
    cout << "문자열 입력>> ";
    getline(cin, text, '\n');

    int cnt = 0;
    for (int i = 0; i < text.length(); i++) {
        if (text[i] == 'a') cnt++;
    }
    cout << "문자 a는 " << cnt << "개 있습니다." << endl;
}

// (2)
int main() {
    string text;
    cout << "문자열 입력>> ";
    getline(cin, text, '\n');

    int cnt = 0, index = 0;
    while (true)
    {
        int fIndex = text.find('a', index);
        if (fIndex == -1) break;
        cnt++;
        index = fIndex + 1;
    }
    cout << "문자 a는 " << cnt << "개 있습니다." << endl;
}

4.

#include <iostream>
using namespace std;

class Sample {
    int *p;
    int size;
public:
    Sample(int n) { size = n; p = new int[n]; }
    void read();
    void write();
    int big();
    ~Sample() { delete[] p; }
};

void Sample::read() {
    for (int i = 0; i < size; i++) {
        cin >> p[i];
    }
}

void Sample::write() {
    for (int i = 0; i < size; i++) {
        cout << p[i] << " ";
    }
    cout << endl;
}

int Sample::big() {
    int max = p[0];
    for (int i = 1; i < size; i++) {
        if (max < p[i]) max = p[i];
    }
    return max;
}

int main() {
    Sample s(10);
    s.read();
    s.write();
    cout << "가장 큰 수는 " << s.big() << endl;
}

5.

#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std;

int main() {
    srand((unsigned)time(0));
    cout << "아래에 한 줄을 입력하세요.(exit를 입력하면 종료합니다)\n";
    string text;
    while (true)
    {
        cout << ">>";
        getline(cin, text, '\n');
        if (text == "exit") break;
        int r = rand();
        int index = r % text.length();
        int alpha = r % ('z' - 'a');
        text[index] = 'a' + alpha;
        cout << text << endl;
    }
}

6.

#include <iostream>
#include <string>
using namespace std;

int main()
{
    cout << "아래에 한 줄을 입력하세요.(exit를 입력하면 종료합니다)" << endl;
    string text;
    while (true)
    {
        cout << ">>";
        getline(cin, text, '\n');
        if (text == "exit") break;
        int start = 0, end = text.length() - 1, temp;
        while (start < end)
        {
            temp = text[start];
            text[start] = text[end];
            text[end] = temp;
            start++;
            end--;
        }
        cout << text << endl;
    }
}

7.

#include <iostream>
using namespace std;

class Circle {
    int radius;
public:
    void setRadius(int radius) { this->radius = radius; }
    double getArea() { return radius * radius * 3.14; }
};

int main() {
    Circle circle[3];
    int r;
    for (int i = 0; i < 3; i++) {
        cout << "원 " << i + 1 << "의 반지름 >> ";
        cin >> r;
        circle[i].setRadius(r);
    }

    int cnt = 0;
    for (int i = 0; i < 3; i++) {
        if (circle[i].getArea() > 100) {
            cnt++;
        }
    }
    cout << "면적이 100보다 큰 원은 " << cnt << "개 입니다" << endl;
}

8.

#include <iostream>
using namespace std;

class Circle {
    int radius;
public:
    void setRadius(int radius) { this->radius = radius; }
    double getArea() { return radius * radius * 3.14; }
};

int main() {
    int n;
    cout << "원의 개수 >> ";
    cin >> n;
    Circle *circle = new Circle [n];

    int r;
    for (int i = 0; i < n; i++) {
        cout << "원 " << i + 1 << "의 반지름 >> ";
        cin >> r;
        circle[i].setRadius(r);
    }

    int cnt = 0;
    for (int i = 0; i < n; i++) {
        if (circle[i].getArea() > 100) {
            cnt++;
        }
    }
    cout << "면적이 100보다 큰 원은 " << cnt << "개 입니다" << endl;

    delete [] circle;
}

9.

#include <iostream>
#include <string>
using namespace std;

class Person {
    string name;
    string tel;
public:
    Person() {}
    string getName() { return name; }
    string getTel() { return tel; }
    void set(string name, string tel) { this->name = name; this->tel = tel; }
};

int main() {
    cout << "이름과 전화 번호를 입력해 주세요" << endl;
    Person person[3];
    string name, tel;
    for (int i = 0; i < 3; i++) {
        cout << "사람 " << i + 1 << ">> ";
        cin >> name >> tel;
        person[i].set(name, tel);
    }

    cout << "모든 사람의 이름은 ";
    for (int i = 0; i < 3; i++) {
        cout << person[i].getName() << " ";
    }

    cout << "\n전화번호 검색합니다. 이름을 입력하세요>>";
    cin >> name;
    for (int i = 0; i < 3; i++) {
        if (person[i].getName() == name) {
            cout << "전화 번호는 " << person[i].getTel() << endl;
            break;
        }
    }
}

10.

#include <iostream>
#include <string>
using namespace std;

class Person {
    string name;
public:
    void setName(string name) { this->name = name; }
    string getName() { return name; }
};

class Family {
    Person *p;
    string name;
    int size;
public:
    Family(string name, int size) {
        p = new Person[size];
        this->name = name;
        this->size = size;
    }
    void show() {
        cout << "Simpson가족은 다음과 같이 " << size << "명 입니다." << endl;
        for (int i = 0; i < size; i++) {
            cout << (p + i)->getName() << '\t';
        }
    }
    void setName(int num, string name) { (p + num)->setName(name); }
    ~Family() { delete[] p; }
};

int main() {
    Family *simpson = new Family("Simpson", 3);
    simpson->setName(0, "Mr. Simpson");
    simpson->setName(1, "Mrs. Simpson");
    simpson->setName(2, "Bart Simpson");
    simpson->show();
    delete simpson;
}

11.

#include <iostream>
using namespace std;

class Container {
    int size;
public:
    Container() { size = 10; }
    void fill() { size = 10; }
    void consume() { size--; }
    int getSize() { return size; }
};

class CoffeeVendingMachine {
    Container tong[3];
    void fill() {
        tong[0].fill();
        tong[1].fill();
        tong[2].fill();
    }
    void selectEspresso() {
        if (tong[0].getSize() > 0 && tong[1].getSize() > 0) {
            tong[0].consume();
            tong[1].consume();
            cout << "에스프레소 드세요" << endl;
        }
        else cout << "원료가 부족합니다." << endl;
    }
    void selectAmericano() {
        if (tong[0].getSize() > 0 && tong[1].getSize() > 1) {
            tong[0].consume();
            tong[1].consume();
            tong[1].consume();
            cout << "아메리카노 드세요" << endl;
        }
        else cout << "원료가 부족합니다." << endl;
    }
    void selectSugarCoffee() {
        if (tong[0].getSize() > 0 && tong[1].getSize() > 1 && tong[2].getSize() > 0) {
            tong[0].consume();
            tong[1].consume();
            tong[1].consume();
            tong[2].consume();
            cout << "설탕커피 드세요" << endl;
        }
        else cout << "원료가 부족합니다." << endl;
    }
    void show() {
        cout << "커피 " << tong[0].getSize() << ", 물 " << tong[1].getSize() << ", 설탕 " << tong[2].getSize() << endl;
    }
public:
    void run() {
        cout << "***** 커피자판기를 작동합니다. *****" << endl;
        while (true)
        {
            cout << "메뉴를 눌러주세요(1:에스프레소, 2:아메리카노, 3:설탕커피, 4:잔량보기, 5:채우기)>> ";
            int n;
            cin >> n;
            switch (n)
            {
            case 1: selectEspresso(); break;
            case 2: selectAmericano(); break;
            case 3: selectSugarCoffee(); break;
            case 4: show(); break;
            case 5: fill(); show(); break;
            }
        }
    }
};

int main() {
    CoffeeVendingMachine coffee;
    coffee.run();
}

12.

#include <iostream>
#include <string>
using namespace std;

class Circle {
    int radius;
    string name;
public:
    void setCircle(string name, int radius) {
        this->name = name;
        this->radius = radius;
    }
    double getArea() { return radius * radius * 3.14; }
    string getName() { return name; }
};

class CircleManager {
    Circle *p;
    int size;
public:
    CircleManager(int size) {
        p = new Circle[size];
        this->size = size;

        string name;
        int radius;
        for (int i = 0; i < size; i++) {
            cout << "원 " << i + 1 << "의 이름과 반지름 >> ";
            cin >> name >> radius;
            p[i].setCircle(name, radius);
        }
    }
    ~CircleManager() { delete[] p; }
    void searchByName();
    void searchByArea();
};

void CircleManager::searchByName() {
    cout << "검색하고자 하는 원의 이름 >> ";
    string name;
    cin >> name;

    for (int i = 0; i < size; i++) {
        if (p[i].getName() == name) {
            cout << "도넛의 면적은 " << p[i].getArea() << endl;
            break;
        }
    }
}

void CircleManager::searchByArea() {
    cout << "최소 면적을 정수로 입력하세요 >> ";
    int n;
    cin >> n;
    cout << n << "보다 큰 원을 검색합니다." << endl;

    for (int i = 0; i < size; i++) {
        if (p[i].getArea() > n) {
            cout << p[i].getName() << "의 면적은 " << p[i].getArea() << ",";
        }
    }
}

int main() {
    cout << "원의 개수 >> ";
    int n;
    cin >> n;
    CircleManager circle(n);
    circle.searchByName();
    circle.searchByArea();
}

13.

#include <iostream>
#include <string>
using namespace std;

class Histogram {
    string text;
public:
    Histogram(string text) { this->text = text; }
    void put(string str) { text.append(str); }
    void putc(char ch) { text += ch; }
    void print();
};

void Histogram::print() {
    cout << text << endl << endl;
    int arr[26] = {0};
    int cnt = 0;

    for (int i = 0; i < text.length(); i++) {
        if(isalpha(text[i])) {
            arr[tolower(text[i]) - 'a']++;
            cnt++;
        }
    }

    cout << "총 알파벳 수 " << cnt << endl << endl;

    for (int i = 0; i < 26; i++) {
        cout << char('a'+i) << " (" << arr[i] << ")\t: ";
        for (int j = 0; j < arr[i]; j++) {
            cout << '*';
        }
        cout << endl;
    }
}

int main() {
    Histogram elvisHisto("Wise men say, only fools rush in But I can't help,\n");
    elvisHisto.put("falling in love with you");
    elvisHisto.putc('-');
    elvisHisto.put("Elvis Presley");
    elvisHisto.print();
}

14.

#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std;

class Player {
    string name;
public:
    void setName(string name) { this->name = name; }
    string getName() { return name; }
};

class GamblingGame {
    Player player[2];
public:
    void start();
};

void GamblingGame::start() {
    srand((unsigned)time(0));
    cout << "***** 갬블링 게임을 시작합니다. *****" << endl;
    string name;
    cout << "첫번째 선수 이름>>";
    cin >> name;
    player[0].setName(name);
    cout << "두번째 선수 이름>>";
    cin >> name;
    player[1].setName(name);
    cin.ignore();

    for (int i = 0;; i++) {
        int index = i % 2;
        cout << player[index].getName() << ":<Enter>";
        if (getchar() == '\n')
        {
            int arr[3] = {rand() % 3, rand() % 3, rand() % 3};
            cout << '\t' << arr[0] << '\t' << arr[1] << '\t' << arr[2] << '\t';
            if (arr[0] == arr[1] && arr[1] == arr[2]) {
                cout << player[index].getName() << "님 승리!!" << endl;
                break;
            }
            else cout << "아쉽군요!" << endl;
        }
    }
}

int main() {
    GamblingGame game;
    game.start();
}